MIDI CHIEF - BLE MIDI Router/mapper

[Elantric]

https://play.google.com/store/apps/details?id=com.octotone.midichief

Control your MIDI USB or Bluetooth devices in app and avoid some trampling

This app can control USB and Bluetooth MIDI devices. Important note: To use one or more USB MIDI devices, it is necessary to use an OTG cable or an OTG HUB connected to the cell phone's USB port. Multiple devices are supported.
It can be used by guitarists, keyboardists and all musicians who want to centralize the sending of MIDI control messages in a single device.